> > 3) AFAIU dropping support for multiple backends is considered as a
> > pre-condition to inclusion of GPC into GCC. GPC release wold be
> > part of GCC release. People trying GPC snapshots would automatically
> > get backend snapshot. I am affraid that for Pascal that means
> > 6-8 months extra delay between including a feature in GPC and first
> > bug reports (and consequently more effort for bug fixing).
>
> The way to avoid this is for front ends to have internal datastructures
> decoupled from those of the rest of GCC and to have a small piece of code
> that does the conversion (like the Ada front end's gigi), then just
> maintain multiple versions of that small piece of code. This seems to
> work well for Ada.
GPC uses backend data structure when possible. I see no reason to
duplicate backend functionality (Ada front is written in Ada, so they
_had to_ duplicate a lot of infrastructure). We can hide (and are doing
that now) most differences in macros.
But there are few tricky questions: I old backends want us to call a
function is it OK to always call a wrapper (empty for new backend)?
Or an actual sample (the most nasty case I have found):
case FLOAT_EXPR:
#ifndef GCC_3_4
case FFS_EXPR:
#endif
here we have moderatly sized switch and moving the case constant
to backend dependent part would move the whole switch, hence the
function containing the switch. Is it acceptable to have something
like:
case FLOAT_EXPR:
CASE_FFS_EXPR
with `CASE_FFS_EXPR' expanding to nothing for new backend.
--
Waldek Hebisch
[EMAIL PROTECTED]
